Poster Presentations

Session Title: VACCINE AND PREVENTION

INFLUENZA ILLNESS BY AGE IN VACCINATED EUROPEAN AND ISRAELI CHILDREN AGED 6 MONTHS TO 17 YEARS

S. Ashkenazi¹, D. Fleming², S. Moren³, C. Ambrose⁴, R. Walker^4
1Schneider Children's Medical Center, Petach-Tikva, Israel, ²Northfield Health Centre, Birmingham, UK, ³CV Therapeutics, Inc., Palo Alto, ⁴MedImmune, LLC, Gaithersburg, USA

Background and aims: Limited culture-confirmed data exist regarding the burden of influenza in European children. In 2002-2003, two prospective, randomized, open-label studies evaluated the efficacy and safety of live, attenuated influenza vaccine (LAIV) versus trivalent inactivated vaccine (TIV) in children aged 6 months to 17 years in Europe and Israel. Data from these studies were analyzed to describe rates of influenza illness by age group and vaccine type.
Methods: Study 1 was conducted in children aged 6-71 months with recurrent respiratory tract infections who received 2 doses of influenza vaccine. Study 2 was conducted in children aged 6-17 years with stable, medically-treated asthma who received 1 dose of vaccine. Post-hoc analyses evaluated the rate of culture-confirmed influenza illness overall and by strain for 4 age groups (0.5-2, 3-5, 6-11, 12-17 years).
Results: The highest incidence of influenza occurred in subjects 6-11 years (51-75 per 1000). The differences were driven by influenza B, the most prevalent strain detected. The incidences of A/H1N1 and A/H3N2 were similar in all age groups.


[Incidence of culture-confirmed influenza]

Conclusions: Despite being from vaccinated children, these data support previous findings that the incidence of influenza B is highest in younger school-aged children. In all age groups analyzed, LAIV recipients had fewer cases of influenza illness than TIV recipients.
(Sponsored by MedImmune. LAIV is not approved outside of the United States.)